1 Malaysia has nothing to do with either Lotus team. It's just a reference to the unification of Malaysia. Both teams are Malaysia-owned, so it's just a way to show national pride. Like the little Italian flag with the number "150" on the Torro Rosso front wing pillar and the name of the Ferrari F150 Italia.
Again, he called his team "1Malaysia" because of the reason I mentioned. It does not stop another Malaysian team from using that exact same term, as it is a term of national pride, not a trademark. It would be like saying no one can use the Italian flag but Ferrari.